In chronic myeloid leukemia, which phase immediately precedes blast crisis?

In chronic myeloid leukemia, which phase immediately precedes blast crisis?

• A. Accelerated phase
• B. Chronic phase
• C. Remission phase
• D. Refractory phase

Answer: (A)

In CML, the disease progresses through stages: chronic, accelerated, and then blast crisis. The phase immediately before blast crisis is the accelerated phase. This stage shows worsening disease features that signal imminent transformation to acute leukemia, such as rising circulating blasts into the 10–19% range in blood or marrow, evolving cytogenetic abnormalities, and increasing or refractory abnormal blood counts. If unchecked, the accelerated phase often progresses to blast crisis, which resembles acute leukemia with high blast counts. The other terms don’t fit the typical progression pattern: remission implies disease control, and a separate refractory phase isn’t part of the standard CML staging sequence.

In CML, the disease progresses through stages: chronic, accelerated, and then blast crisis. The phase immediately before blast crisis is the accelerated phase. This stage shows worsening disease features that signal imminent transformation to acute leukemia, such as rising circulating blasts into the 10–19% range in blood or marrow, evolving cytogenetic abnormalities, and increasing or refractory abnormal blood counts. If unchecked, the accelerated phase often progresses to blast crisis, which resembles acute leukemia with high blast counts. The other terms don’t fit the typical progression pattern: remission implies disease control, and a separate refractory phase isn’t part of the standard CML staging sequence.